Anthraquinone-functionalized reduced graphene oxide as a negative electrode for aqueous Ni(OH)<sub>2</sub>/NiOOH hybrid cells


Sertkol S. B., Momchilov A. A., Esat B., Sertkol M.

JOURNAL OF POWER SOURCES, vol.669, 2026 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 669
  • Publication Date: 2026
  • Doi Number: 10.1016/j.jpowsour.2026.239440
  • Journal Name: JOURNAL OF POWER SOURCES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC
  • Istanbul University Affiliated: No

Abstract

Aqueous organic-inorganic hybrid systems offer a safe and sustainable platform for high-power energy storage, yet mitigating redox instability in carbon-supported organic electrodes remains challenging. This study reports a full-cell pairing a reduced graphene oxide (RGO) electrode, covalently functionalized with anthraquinone (AQ) units, with a Ni(OH)2 positive electrode in alkaline electrolyte. The nitrene-grafted RGO-methyl AQ material immobilizes AQ units on a conductive carbon framework, mitigating dissolution and enabling effective electron transfer. Electrochemical analysis reveals a hybrid charge-storage mechanism combining reversible AQ redox with capacitive buffering from RGO. The RGO-methyl AQ & Vert;Ni(OH)2/NiOOH full-cell delivers an average operating voltage of 0.89 V and a specific capacity of 139.6 mAh g-1 (anode mass) at 0.09C. It retains 84 % of its capacity (51 mAh g-1) after 101 cycles at 12.7C and remains operational at 33C. The anode-based energy density decreases from 61 Wh kg-1 at 2C to 34 Wh kg-1 at 33C. When projected to a practical device assuming a 25-40 % active-mass fraction, the estimated power density (281-449 W kg-1) lies within the lower range of commercial high-power NiMH systems. These results identify covalently grafted AQ-RGO as a promising electroactive anode candidate for sustainable, critical-metal-free NiMH-type chemistries, while explicitly highlighting performance limits associated with interfacial instability.